JP2009041946A - Optical image measuring device - Google Patents

Abstract

An object is to image a fine structure of a deep tissue of an object to be measured.
An optical image measurement device 1 divides low-coherence light into signal light and reference light by interference light generation means including a light source 2, an optical fiber bundle 5, a reflection unit 6, a reference mirror 9, and a beam splitter 12. Then, the interference light is generated by superimposing the signal light passing through the measured object 5000 and the reference light passing through the reference mirror 9. The two-dimensional photosensor arrays 14 and 15 detect interference light. The computer 16 forms an image of the measured object 5000 based on the detection result. A tomographic image of the deep tissue of the measured object 5000 is obtained by inserting the optical fiber bundle 5 into the measured object 5000 and performing measurement. Furthermore, since the optical image measurement device 1 performs measurement using the OCT technique, it is possible to form a high-resolution image of the deep tissue of the measurement object 5000.
[Selection] Figure 1

Description

  The present invention relates to an optical image measurement device that forms an image of an object to be measured using OCT (Optical Coherence Tomography) technology.

  2. Description of the Related Art In recent years, optical image measurement technology that forms an image of the surface or inside of an object to be measured using a laser light source or the like attracts attention. Since the optical image measurement technique does not have invasiveness to the human body like conventional X-ray CT, it is particularly expected to be applied to the medical field.

  An example of a typical technique in the optical image measurement technique is an OCT technique (referred to as an optical coherence tomography method). This technology uses the low coherence of a broadband light source with a wide spectral width, such as a super luminescent diode (SLD), for example, to improve reflected light and transmitted light from the object to be measured on the order of μm. It is possible to detect with a high distance resolution (see Non-Patent Document 1, for example).

  As an example of an apparatus using the OCT technique, a conventional optical image measurement apparatus using a Michelson interferometer will be described. The basic configuration of such an optical image measurement device is shown in FIG. An optical image measurement apparatus 1000 shown in FIG. 10 is an apparatus that forms an image of an object 1005 to be measured, and includes a broadband light source 1001, a mirror 1002, a beam splitter 1003, and a photodetector 1004. The light beam output from the broadband light source 1001 is split into reference light R and signal light L by a beam splitter 1003. The reference light R travels toward the mirror 1002. The signal light S travels toward the object 1005 to be measured.

  As shown in FIG. 10, the traveling direction of the signal light S is defined as the z direction, and the orthogonal plane is defined as the xy plane. The mirror 1002 can be displaced in the direction of a double-sided arrow in FIG. 10 by a drive mechanism (not shown). This is called z-scan.

  The reference light R undergoes a Doppler frequency shift by z-scan when reflected by the mirror 1002. On the other hand, the signal light S is reflected by the surface or inner layer of the measured object 1005. The object to be measured 1005 is a scattering medium, and the reflected light of the signal light S is considered to be a diffuse wavefront having a messy phase including multiple scattering. The signal light S that has passed through the measured object 1005 and the reference light R that has passed through the mirror 1002 are superimposed by the beam splitter 1003 to generate interference light.

  In the image measurement using the OCT technique, the component of the signal light S in which the optical path length difference between the signal light S and the reference light R is within the coherent length (coherence distance) of the light source in the order of μm and has a phase correlation with the reference light R. Only cause interference with the reference light R. That is, only the coherent signal light component of the signal light S selectively interferes with the reference light R. From this principle, the light reflection profile of the inner layer of the measured object 1005 is measured by z-scanning the position of the mirror 1002 to change the optical path length of the reference light R. Further, the signal light S can be scanned in the xy plane direction. It is possible to form a two-dimensional tomographic image of the subject 1005 by detecting the interference light while performing scanning in the z direction and the xy plane direction and analyzing the detection result (heterodyne signal). Yes (see Non-Patent Document 1).

  According to the above method, since it is necessary to sequentially measure various parts of the measured object 1005 in the depth direction (z direction) and the tomographic plane direction (xy plane direction), there is a problem that the measurement time becomes long. There is. In consideration of the measurement principle, it is difficult to reduce the measurement time.

  A technique for solving this problem has also been devised. A basic configuration of an apparatus using this method is shown in FIG. The optical image measurement device 2000 includes a xenon lamp 2001, a mirror 2002, a beam splitter 2003, a two-dimensional photosensor array 2004, and lenses 2006 and 2007. A plurality of light receiving elements are arranged on the light receiving surface of the two-dimensional photosensor array 2004.

  The light beam output from the light source 2001 becomes a parallel light beam whose beam diameter is expanded by the lenses 2006 and 2007. The beam splitter 2003 splits this parallel light beam into reference light R and signal light S. The signal light S is irradiated to a range corresponding to the beam diameter. Therefore, the signal light S that has passed through the measured object 2005 includes information on the measured object 2005 in the irradiation range.

  The reference light R and the signal light S are superimposed by the beam splitter 2003 to generate interference light. The interference light has a beam diameter corresponding to the signal light S or the like. The two-dimensional photosensor array 2004 detects interference light by a two-dimensional light receiving surface. Based on the detection result, a tomographic image of the object to be measured 2005 in the irradiation range is formed. Therefore, a tomographic image of the object to be measured 2005 can be quickly acquired without scanning the light beam.

  As such a non-scanning optical image measuring device, the one described in Non-Patent Document 2 is known. In this apparatus, a plurality of heterodyne signals output from a two-dimensional photosensor array are input to a plurality of signal processing systems arranged in parallel, and the amplitude and phase of each heterodyne signal are detected.

  However, in such a configuration, in order to increase the spatial resolution of the image, it is necessary to increase the number of elements in the array, and it is also necessary to prepare a signal processing system having the number of channels corresponding to the number of elements. Therefore, it is difficult to realize a satisfactory resolution in fields such as medicine and industry.

  In view of this, the present inventors have proposed the following non-scanning optical image measurement device in Patent Document 1. The optical image measurement device includes a light source that emits a light beam, a signal beam that passes through the subject placement position where the subject is placed, and the light beam emitted from the light source and the subject placement position. Divided into reference light that passes through an optical path different from the optical path, and generates interference light by superimposing the signal light after passing through the subject placement position and the reference light passing through the different optical path. An interference optical system, a frequency shifter that relatively shifts the frequency of the signal light and the frequency of the reference light, and the interference optical system receives the interference light to receive the interference light. Are further divided into two, and the interference light divided into two is periodically blocked to generate two rows of interference light pulses having a phase difference of 90 degrees, and the two rows Each of the interfering light pulses The light sensor and the light sensor are arranged spatially and each have a plurality of light receiving elements that independently obtain a light receiving signal. The light receiving signals obtained by the light sensor are integrated. A signal processing unit configured to generate a signal corresponding to each point of interest on the propagation path of the signal light on the surface or inner layer of the subject placed at the subject placement position;

  This optical image measuring device divides the interference light of the reference light and the signal light into two parts and receives them by two light sensors (two-dimensional light sensor array), and a light blocking device is arranged in front of both sensor arrays. And configured to sample the interference light. Then, by providing a phase difference of π / 2 in the sampling period of the two divided interference lights, the intensity of the signal light and the reference light constituting the background light component of the interference light and the orthogonal component of the phase of the interference light ( sine component and cos component), and by subtracting the intensity of the background light component contained in the output from both sensor arrays from the output of both sensor arrays, two phase quadrature components of the interference light are calculated, The amplitude of the interference light is obtained using the calculation result.

  A commercially available image sensor such as a CCD (Charge-Coupled Device) camera is widely used as the two-dimensional photosensor array. However, a CCD image sensor currently on the market has a low frequency response characteristic, and it has been conventionally recognized that it cannot follow the beat frequency of a heterodyne signal of about several KHz to several MHz. The optical image measuring apparatus described in Patent Document 1 by the present inventors is characterized by the fact that the measurement is performed using the low response characteristics after sufficiently recognizing the problem. .

  The optical image measurement apparatus as described above has an advantage that it can describe the fine structure of the object to be measured, for example, can acquire a cell level image of a living body, but the deep part where the light irradiated on the surface of the object to be measured cannot reach The image of the structure could not be imaged. For example, with a conventional optical image measurement device, an image of the fundus, skin tissue, etc. of a living body could be acquired, but a deep tissue such as an internal organ could not be imaged.

  In the present specification, a portion having a depth that the light irradiated on the surface of the object to be measured cannot reach, in other words, a portion having a depth that cannot acquire an image when light is irradiated from the surface, is simply expressed as “ Sometimes called “deep”. The depth of the deep part varies depending on the object to be measured, and also varies depending on the wavelength and intensity of light.

  An endoscope is known as an apparatus for imaging a deep tissue of a measurement object. An endoscope is for examining the inside of a body by inserting a part of the apparatus into an opening (natural opening or artificial opening) on the surface of a subject (for example, see Patent Document 2).

  As described above, the endoscope can image the structure of the deep part of the object to be measured, but cannot describe the fine structure as in the optical image measurement device.

JP 2001-330558 A JP 2007-125277 A Naohiro Tanno, “Optics”, Vol. 28, No. 3, 116 (1999) K. P. Chan, M.C. Yamada, H .; Inaba, “Electronics Letters”, Vol. 30, 1753, (1994)

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an optical image measurement device capable of imaging a fine structure of a deep tissue of an object to be measured.

  In order to achieve the above object, the invention according to claim 1 divides low-coherence light into signal light and reference light, and the signal light passing through the object to be measured and the reference light passing through the reference object Interference light generation means for generating interference light by superimposing, detection means for detecting the interference light, and image forming means for forming an image of the object to be measured based on the detection result of the interference light In the optical image measurement device, the interference light generation unit emits signal light divided from low-coherence light from one end, and guides the signal light incident on the one end via the object to be measured. Light guide means for generating interference light by superimposing the guided signal light with reference light.

  The invention according to claim 2 is the optical image measuring device according to claim 1, wherein the light guide means has flexibility.

  The invention according to claim 3 is the optical image measurement device according to claim 1 or claim 2, wherein the light guide means converts low-coherence light incident from the other end into signal light and reference light. The signal light is emitted from the one end, and the signal light incident from the one end via the object to be measured is guided to the other end and emitted, and the reference light is emitted. Is emitted from the other end, and the interference light generation unit generates interference light by superimposing the signal light and the reference light respectively emitted from the other end.

  The invention according to claim 4 is the optical image measurement device according to any one of claims 1 to 3, wherein the light guide means includes an optical fiber bundle. To do.

  The invention according to claim 5 is the optical image measurement device according to claim 3, wherein the light guide means includes an optical fiber bundle having both ends of the one end and the other end, and the dividing means. Includes a reflecting means for reflecting a part of the low coherence light guided toward the one end and dividing the low coherence light into signal light and reference light.

  The invention described in claim 6 is the optical image measurement device according to claim 4 or 5, wherein a microlens is provided at the one end of each fiber of the optical fiber bundle. Features.

  The invention according to claim 7 is the optical image measurement device according to any one of claims 4 to 6, wherein the detection means includes a plurality of fibers included in the optical fiber bundle. It includes a two-dimensional photosensor array that simultaneously detects a plurality of interference lights based on a plurality of guided signal lights.

  The invention according to claim 8 is the optical image measurement device according to any one of claims 4 to 6, wherein the interference light generation means includes a plurality of optical fiber bundles included in the optical fiber bundle. Signal light is sequentially guided to the fiber, the detecting means sequentially detects interference light based on the sequentially guided signal light, and the image forming means is configured to detect each interference light detected sequentially. Based on the above, images of a plurality of different parts of the object to be measured are sequentially formed.

  The invention according to claim 9 is the optical image measurement device according to any one of claims 1 to 8, wherein the interference light generation means includes the optical path length of the signal light and the reference. An optical member for matching the optical path length of the light is included.

  The invention according to claim 10 is the optical image measurement device according to any one of claims 1 to 8, wherein the interference light generating means is a dispersion of the signal light. An optical member for matching the influence and the influence of dispersion applied to the reference light is included.

  The invention according to claim 11 is the optical image measurement device according to claim 9 or 10, wherein the optical member is provided on an optical path of the reference light.

  The optical image measurement device according to the present invention divides low-coherence light into signal light and reference light, and generates interference light by superimposing the signal light passing through the object to be measured and the reference light passing through the reference object. The interference light is detected, and an image of the object to be measured is formed based on the detection result of the interference light. The image formed by this optical image measurement device is a high-resolution image using OCT technology.

  Furthermore, this optical image measuring device is provided with light guiding means. The light guide means is configured to emit signal light divided from the low-coherence light from one end and guide the signal light incident from the one end via the object to be measured. The optical image measurement device acts to generate interference light by superimposing the signal light guided by the light guide means with the reference light. By adopting such a configuration, it is possible to perform measurement in a state where the light guide means is disposed near the deep tissue of the object to be measured.

  According to such an optical image measurement device, it is possible to image the fine structure of the deep tissue of the object to be measured.

  An example of an embodiment of an optical image measurement device according to the present invention will be described in detail with reference to the drawings.

  The optical image measuring device according to the present invention can acquire an image of a deep part of an object to be measured like an endoscope, and can also image even the fine structure thereof. Therefore, when applied to the medical field or the biological field, it is also possible to acquire an image (for example, an image of a cell level such as a viscera or a brain) representing a fine structure of internal tissue of a living body.

  The optical image measurement apparatus using the OCT technology has a Fourier domain (Frequency domain) type, a full-field type, a swept source type, etc., depending on the measurement mode. There are various types.

  The Fourier domain type optical image measurement device spectrally decomposes interference light and forms an image based on the frequency distribution. In the Fourier domain type, an image is formed by scanning a measurement region of an object to be measured with signal light, and an image of the measurement region is formed. This type of optical image measurement device is disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-117714.

  Similarly, the swept source type optical image measuring device scans the signal light to perform measurement. In the swept source type, a light source (high-speed wavelength scanning laser) that switches and outputs light of various frequencies at high speed is used instead of spectrally decomposing interference light. This type of optical image measurement device is disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-24677.

  Further, the full-field optical image measuring device is characterized in that, as described in Patent Document 1, the object to be measured can be irradiated with a light beam having a certain beam diameter, and an image in the irradiation range can be formed at a time. Is. In the Fourier domain type or the swept source type, an image of a cross section extending in the depth direction of the object to be measured is obtained. In the full field type, an image of a cross section perpendicular to the depth direction is obtained. In the full field type, it is also possible to scan with signal light in order to change the measurement site of the object to be measured.

  Hereinafter, a full-field optical image measurement device will be described as a first embodiment according to the present invention. As a second embodiment, a Fourier domain type and a swept source type optical image measurement device will be described.

<First Embodiment>
An application example of the present invention to a full-field type optical image measurement device will be described.

[Device configuration]
An example of a schematic configuration of the optical image measurement device according to this embodiment is shown in FIG. The optical image measurement device 1 is a device for acquiring a tomographic image of the object 5000 to be measured.

  The optical image measurement device 1 includes a light source 2 that outputs broadband light (low coherence light). The broadband light output from the light source 2 has a predetermined beam diameter.

  The light source 2 includes a halogen lamp, for example. This halogen lamp outputs non-polarized broadband light. The light source 2 may include an optical fiber bundle that guides the output light from the halogen lamp, a Kohler illumination optical system for uniformly illuminating the irradiation field of the output light, and the like.

  In addition to the halogen lamp, any light source that outputs non-polarized broadband light can be used. For example, an arbitrary thermal light source (a light source based on black body radiation) such as a xenon lamp can be applied. It is also possible to use a light source that outputs a randomly polarized broadband light.

  Here, non-polarized light means a polarization state including linearly polarized light, circularly polarized light, and elliptically polarized light. Random polarization means a polarization state having two linearly polarized light components orthogonal to each other and the power of each linearly polarized light component changes randomly in time (see, for example, Japanese Patent Laid-Open No. 7-92656). Hereinafter, only the case of non-polarized light will be described in detail, but in the case of random polarized light, the same effect can be obtained with the same configuration.

  Broadband light output from a halogen lamp or the like includes light of various bands. The light source 2 includes a filter that transmits only a predetermined band of the broadband light. The band transmitted by this filter is determined according to the resolution, measurement depth, etc., and is set to a band having a center wavelength of about 760 nm and a wavelength width of about 100 nm, for example. In this case, an image with a resolution of about 2 μm can be acquired in each of the depth direction of the object to be measured 5000 (z direction shown in FIG. 1) and the direction orthogonal to the depth direction (lateral direction). The light transmitted through this filter is also called broadband light.

  The broadband light output from the light source 2 passes through the beam splitter 3 and the polarizing element 4 and enters the base end portion 5 a of the optical fiber bundle 5. For example, the polarizing element 4 allows only a 45-degree linearly polarized light component of broadband light to pass through.

  The optical fiber bundle 5 is a bundle of a plurality of optical fibers. One end of each optical fiber is disposed at the proximal end portion 5a, and the other end is disposed at the distal end portion 5b. The plurality of optical fibers are bundled so that their cross sections are arranged in an array.

  As the optical fiber bundle 5, for example, one that is generally used in an apparatus such as an endoscope can be applied (see, for example, JP-A-2006-130183). The optical fiber bundle 5 is configured as, for example, a probe that can be inserted into a subject as in an endoscope. The optical fiber bundle 5 (probe) has flexibility similar to the probe of an endoscope, and can be configured to be deformable when inserted into a subject. It is also possible to provide a mechanism for arbitrarily deforming the shape of the optical fiber bundle 5 (probe). These configurations are the same as, for example, a conventional endoscope probe.

  The number of optical fibers included in the optical fiber bundle 5 is one of the factors that determine the lateral resolution of the optical image measurement device 1. The optical fiber bundle 5 has an appropriate number of optical fibers according to the use of the optical image measuring device 1 and the like. The optical fiber bundle 5 is an example of the “light guide” in the present invention.

  The optical fiber bundle 5 is provided with a reflecting portion 6. The reflector 6 reflects a part of the broadband light that travels in the optical fiber bundle 5 toward the tip 5b. The broadband light reflected by the reflector 6 is used as reference light. On the other hand, the broadband light transmitted through the reflecting portion 6 is used as signal light. The reflector 6 is an example of the “dividing means” and “reflecting means” of the present invention.

  The reflection unit 6 can be provided at an arbitrary position of the optical fiber bundle 5. For example, as shown in FIG. 1, the reflection part 6 may be provided at positions other than the end parts 5a and 5b of the optical fiber bundle 5, or the reflection part 6 may be provided at the tip part 5b.

  The reflection part 6 is formed, for example, by vapor-depositing a semitransparent film on the optical fiber bundle 5. Moreover, it is also possible to use a half mirror as the reflection part 6. For example, a configuration in which the optical fiber bundle 5 is divided into a part on the base end part 5a side and a part on the tip end part 5b side and a half mirror is disposed at the division position can be applied. Further, a half mirror may be provided between the distal end portion 5b and the measured object 5000, between the proximal end portion 5a and the polarizing element 4, or the like.

  The reference light composed of broadband light reflected by the reflecting unit 6 is emitted from the base end part 5 a of the optical fiber bundle 5, passes through the polarizing element 4, and is reflected by the beam splitter 3. Further, the reference light is reflected by the beam splitter 7, passes through the wave plate (λ / 4 plate) 8, and reaches the reference mirror 9.

  The reference light reflected by the reference mirror 9 passes through the wave plate 8 again, passes through the beam splitter 7, is reflected by the reflecting mirror 10, and reaches the beam splitter 12.

  The reference mirror 9 is movable in the direction of the double-sided arrow A shown in FIG. 1 (see the reference mirror moving mechanism 9A shown in FIG. 3). Thereby, images of various depth positions of the measured object 5000 can be acquired. Further, by changing the position of the reference mirror 9, it becomes possible to generate interference light having different phases (described later). The reference mirror 9 is an example of the “reference object” in the present invention.

  The reference light that has reached the beam splitter 12 is a broadband light that was initially unpolarized, passes through the polarizing plate 4, passes through the polarizing plate 4 again, and further passes through the wave plate 8 twice. Therefore, the polarization characteristic of the reference light reaching the beam splitter 12 is circularly polarized light.

  On the other hand, the signal light composed of broadband light transmitted through the reflecting portion 6 is emitted from the tip portion 5 b of the optical fiber bundle 5.

  As shown in FIG. 2, a microlens 5β is provided at the distal end portion 5 b of the optical fiber bundle 5 for each optical fiber 5α of the optical fiber bundle 5. The microlens 5β functions as an objective lens that converges signal light emitted from the end portion 5b side of the optical fiber 5α.

  The signal light applied to the measured object 5000 is reflected and scattered at various depth positions of the measured object 5000. The reflected or scattered light of the signal light enters the optical fiber 5α via the microlens 5β. Further, the signal light is guided by the optical fiber bundle 5 and emitted from the base end portion 5a.

  The signal light emitted from the base end portion 5 a passes through the polarizing element 4, is reflected by the beam splitter 3, passes through the beam splitter 7, is reflected by the reflecting mirror 11, and reaches the beam splitter 12.

  The signal light that has reached the beam splitter 12 is a non-polarized broadband light that has passed through the polarizing plate 4 (45-degree linearly polarized light), the measured object 5000, and the polarizing plate 4 again. It is. Therefore, the polarization characteristic of the signal light reaching the beam splitter 12 is linearly polarized light.

  The reference light reflected by the beam splitter 12 and the signal light transmitted through the beam splitter 12 are superimposed on each other to generate interference light. The interference light is divided into two polarization components by the polarization beam splitter 13 and detected by the two-dimensional photosensor arrays 14 and 15.

  That is, the S-polarized component of the interference light is reflected by the polarization beam splitter 13 and detected by the two-dimensional photosensor array 14. On the other hand, the P-polarized component of the interference light passes through the polarization beam splitter 13 and is detected by the two-dimensional photosensor array 15.

  Each of the two-dimensional photosensor arrays 14 and 15 has a two-dimensional light receiving surface. The S-polarized component and the P-polarized component respectively include the same number of beams as the optical fiber 5α that guides the signal light and the reference light. These beams are arranged similarly to the arrangement of the cross section of the optical fiber 5α.

  When each of the two-dimensional photosensor arrays 14 and 15 detects the polarization component of the interference light, it sends a signal (detection signal) representing the detection result to the computer 16.

  Each of the two-dimensional photosensor arrays 14 and 15 is constituted by an arbitrary image sensor having a two-dimensional light receiving surface. For example, a CCD image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor can be used as the two-dimensional photosensor arrays 14 and 15.

  The two-dimensional photosensor arrays 14 and 15 are an example of the “detecting means” in the present invention. The detection means does not need to be composed of such a pair of image sensors, and the detection means composed of one or a plurality of image sensors can be appropriately configured. Also included in the “detection means” is a polarization beam splitter 13 for causing the two-dimensional photosensor arrays 14 and 15 to detect the polarization component of the interference light.

  An aperture stop and an imaging lens (group) are provided between the beam splitter 12 and the polarization beam splitter 13 (not shown). The aperture stop limits the beam diameter of the interference light. The imaging lens condenses the interference light (polarized component thereof) and forms an image on the light receiving surfaces of the two-dimensional photosensor arrays 14 and 15.

  As shown in FIG. 3, the computer 16 includes a control unit 17, a display unit 18, an operation unit 19, and a signal processing unit 20.

  The control unit 17 controls each unit of the optical image measurement device 1. For example, the control unit 17 controls the output of broadband light by the light source 2, controls the reference mirror moving mechanism 9 </ b> A for moving the reference mirror 9, controls the exposure time of the two-dimensional photosensor arrays 14 and 15, and the display unit 18. Controls display processing by.

  The control unit 17 includes a microprocessor such as a CPU. The control unit 17 includes a storage device such as a RAM, a ROM, and a hard disk drive. The hard disk drive stores a computer program for device control in advance. As the microprocessor operates in accordance with this computer program, the control unit 17 controls each part of the apparatus.

  The control unit 17 may include a communication device for performing data communication with an external device. Communication devices include LAN cards and modems. Thereby, the control part 17 can acquire various information from an external database, or can register information in a database. In addition, information can be acquired from an ophthalmic apparatus such as an examination apparatus, or information can be transmitted to the ophthalmic apparatus. The control unit 17 can also communicate with information systems of other medical departments and information systems of the entire hospital.

  The display unit 18 is controlled by the control unit 17 to display various information. The display unit 18 includes an arbitrary display device such as an LCD or a CRT display.

  The operation unit 19 is used by an operator to operate the optical image measurement device 1 and input various kinds of information. The operation unit 19 includes an arbitrary operation device and input device such as a mouse, a keyboard, a joystick, a trackball, and a dedicated control panel.

  The signal processing unit 20 processes various signals. The signal processing unit 20 includes a microprocessor such as a CPU, a storage device such as a RAM, a ROM, and a hard disk drive. A computer program for signal processing is stored in advance in this storage device. As the microprocessor operates in accordance with this computer program, the signal processing unit 20 executes various signal processing.

  The signal processing unit 20 forms an image of the measured object 5000, particularly a tomographic image, based on the detection signals output from the two-dimensional photosensor arrays 14 and 15. This tomographic image is an image in a cross section orthogonal to the z direction in FIG. The formation process by the signal processing unit 20 will be described later. The signal processing unit 20 is an example of the “image forming unit” in the present invention.

[Mode of operation]
An operation mode of the optical image measurement device 1 will be described. Here, a case will be described in which an image of a tissue (deep tissue) in a subject is acquired like an endoscope.

  First, the control unit 17 controls the light source 2 to output broadband light. In this operation mode, continuous light of broadband light is output.

  The examiner inserts the optical fiber bundle 5 (probe) into the subject from the distal end portion 5b side. At this time, the reference mirror 9 is arranged at a predetermined initial position, for example. In this state, the optical image measurement device 1 acquires an image in the subject and displays it on the display unit 18. This image is displayed at a predetermined time interval (frame rate), for example. The examiner guides the optical fiber bundle 5 to the vicinity of the deep tissue to be observed while observing this image. Note that a normal endoscope may be inserted into the subject, and the optical fiber bundle 5 may be guided with reference to the endoscope image.

  The examiner adjusts the position of the reference mirror 9 so that an image having a predetermined depth of the deep tissue to be observed can be obtained. This process is performed, for example, when the examiner operates the operation unit 19 and the control unit 17 controls the reference mirror moving mechanism 9A accordingly. When the position adjustment of the reference mirror 9 is completed, the examiner operates the operation unit 19 to instruct start of image acquisition.

Upon receiving this instruction, the control unit 17 controls the reference mirror moving mechanism 9A as necessary to set the optical path length of the reference light to the first optical path length. The first optical path length corresponds to the observation depth (z coordinate value) of the deep tissue. The controller 17 controls the exposure time of each of the two-dimensional photosensor arrays 14 and 15. Two-dimensional photosensor array 14 outputs a detection signal C _A detects the S-polarized light component of the interference light. Two-dimensional photosensor array 15 outputs a detection signal C _B detects the P-polarized light component of the interference light.

The S-polarized component and the P-polarized component of the interference light have a phase difference of 90 degrees (π / 2). Therefore, the detection signal C _A and the detection signal C _B have a phase difference of 90 degrees. The detection signals C _A and C _B can be expressed by the following equations, respectively.

Here, I _s (x, y) represents the intensity of the signal light, and I _r (x, y) represents the intensity of the reference light. Φ (x, y) represents an initial phase difference. Each detection signal C _A , C _B includes a background light component (non-interference component, DC component) I _s (x, y) + I _r (x, y). Further, the detection signal C _A includes an interference component composed of a cos component, and the detection signal C _B includes an interference component composed of a sin component.

As shown in equations (1) and (2), each of the detection signals C _A and C _B includes only space (x direction orthogonal to the z direction, y direction) as a variable, and does not include time as a variable. . That is, the interference signal according to the present embodiment includes only a spatial change.

Next, the control unit 17 controls the reference mirror moving mechanism 9A to switch the optical path length of the reference light to the second optical path length. The second optical path length also corresponds to the site to be observed. The controller 17 controls the exposure times of the two-dimensional photosensor arrays 14 and 15 to output new detection signals C _A ′ and C _B ′.

Here, the first optical path length and the second optical path length are such that the detection signal C _A and the detection signal C _A ′ have a phase difference of 180 degrees (π), and the detection signal C _B and the detection signal C _B. Is set in advance so as to be a distance interval having a phase difference of 180 degrees (π). Since the detection signals C _A and C _B have a phase difference of 90 degrees, four detection signals C _A , C _B , C _A ′, and C _B ′ for each phase difference of 90 degrees are obtained. Become.

The signal processing unit 20 adds the detection signals C _A and C _A ′ (phase difference 180 degrees), and divides the sum by 2 to obtain the background light component I _s (x, y) + I _r (x, y ) Is calculated. This calculation process may be performed using the detection signals C _B and C _B ′ (phase difference 180 degrees).

Further, the signal processing unit 20 divides the obtained background light component I _s (x, y) + I _r (x, y) from each detection signal C _A , C _B to obtain an interference component (cos component, sin component). Ask. The signal processing unit 20 forms an image in a cross section in a direction (lateral direction) perpendicular to the z-direction by calculating the square sum of the interference components of the respective detection signals C _A, C _B.

The control unit 17 displays the formed image on the display unit 18 in response to an operation on the operation unit 19, for example. This image forming process may be performed using the detection signals C _A ′ and C _B ′ (phase difference 180 degrees).

  The control unit 17 can sequentially form cross-sectional images at various depth positions of the deep tissue to be observed by sequentially changing the optical path length of the reference light and repeating the above processing.

  In this process, the control unit 17 controls the two-dimensional photosensor arrays 14 and 15 to output detection signals at a predetermined frame rate and at the same timing. Further, the control unit 17 synchronizes the frame rate, the exposure timing of the two-dimensional photosensor arrays 14 and 15, the movement timing of the reference mirror 9, and the change timing of the optical path length of the reference light.

  At this time, the exposure time of the two-dimensional photosensor arrays 14 and 15 is set shorter than the frame rate. For example, the frame rate of the two-dimensional photosensor arrays 14 and 15 can be set to 30 f / s, and the exposure time can be set to about 30 to 50 μs.

  Further, by using broadband light having a center wavelength of about 760 nm and a wavelength width of about 100 nm, an image with a resolution of about several μm can be acquired. For example, when the object to be measured is the human eye (refractive index n = 1.33), assuming that the wavelength of the broadband light is Gaussian, the theoretical value of the resolution of the acquired image is about 1.8 μm. .

  The deep tissue image acquired in this way is stored in an arbitrary storage device such as a hard disk drive of the control unit 17.

[Action / Effect]
The operation and effect of the optical image measurement device 1 will be described.

  The optical image measuring device 1 divides low-coherence light (broadband light) into signal light and reference light, and generates interference light by superimposing the signal light passing through the object to be measured and the reference light passing through the reference object. Interference light generating means, two-dimensional photosensor arrays 14 and 15 for detecting the interference light, and a signal processing unit 20 for forming an image of the object to be measured based on the detection result of the interference light.

  Here, the interference light generation means includes at least the light source 2, the optical fiber bundle 5, the reflection unit 6, the reference mirror 9, and the beam splitter 12.

  The optical fiber bundle 5 is an example of the “light guide” of the present invention as described above. That is, the optical fiber bundle 5 acts to emit the signal light divided from the low-coherence light from the tip portion 5b and guide the signal light incident from the tip portion 5b via the object to be measured. The interference light generation means acts to generate interference light by superimposing the signal light guided by the optical fiber bundle 5 with the reference light.

  According to such an optical image measuring device 1, for example, the optical fiber bundle 5 can be inserted into the subject, and the distal end portion 5b can be placed near the deep tissue of the object 5000 to be measured. .

  Furthermore, according to the optical image measurement device 1, it is possible to form an image having a resolution of μm level of a deep tissue by using the OCT technique.

  Thus, according to the optical image measurement device 1, it is possible to image the fine structure of the deep tissue of the object to be measured.

  Further, by using the flexible optical fiber bundle 5, for example, the optical fiber bundle 5 can be suitably inserted into the subject. In particular, when the path from the opening on the surface of the subject to the deep tissue is bent, the optical fiber bundle 5 can be suitably guided to the vicinity of the deep tissue.

  Further, the optical fiber bundle 5 includes a reflecting portion 6 that divides low-coherence light incident from the base end portion 5a into signal light and reference light. Then, the signal light is emitted from the distal end portion 5b, passes through the object to be measured, is incident on the optical fiber bundle 5 from the distal end portion 5b, is guided to the proximal end portion 5a, and is emitted, while the reference light is The light exits from the base end 5a. The signal light and the reference light emitted from the base end portion 5a are superimposed on each other to generate interference light.

  In this way, by sharing a part of the optical path of the signal light and a part of the optical path of the reference light, the optical path of the reference light alone can be shortened, and the apparatus configuration can be simplified. Become. That is, in an optical image measurement device using OCT technology, unlike devices such as endoscopes and confocal microscopes, it is necessary to match the optical path length of the signal light with the optical path length of the reference light in order to generate interference light. However, by configuring as in this embodiment, it is possible to satisfy the request suitably.

  Note that the length of the optical path between the beam splitter 7 and the reference mirror 9 in the optical path of the reference light alone is equal to the length between the reflection unit 6 and the observation depth position of the measured object 5000. That is, the observation depth position (z coordinate value) can be changed by moving the reference mirror 9 and changing the length of the optical path.

  “Optical path length (optical path length)” means not the length of the optical path at a simple spatial distance, but the refractive index of the optical member means the length of the optical path at an optical distance considering the arrangement, etc. It is.

[Modification]
A modification of the full-field optical image measurement device will be described.

  In the above embodiment, the optical image measurement device 1 of the type that detects the polarization component of the interference light has been described. However, the full-field optical image measurement device is not limited to this. For example, as described in JP 2001-330558 A, a configuration in which different phase components of interference light are extracted using a light blocking device (shutter) can be applied.

However, the type using the polarization characteristic as in the above-described embodiment has an advantage that complicated components such as a shutter are unnecessary and precise control of the shutter is unnecessary. In addition, according to the type using polarization characteristics, four components (C _A , C _B , C _A ′, C _B ′) necessary for forming an image can be acquired by two measurements, and the measurement time can be shortened. (There are other types that have to be measured three times or more).

  In the above embodiment, when the optical fiber bundle 5 is long, or when the reflecting portion 6 is disposed closer to the base end portion 5a, it may be necessary to increase the optical path length of the reference light alone. In such a case, it is possible to provide an optical member that extends the optical path length of the reference light. This optical member is disposed on the optical path of the reference light alone, for example, between the beam splitter 7 and the reference mirror 9. Thereby, interference light can be generated while maintaining information included in the signal light. This optical element is formed of a material having a large refractive index, for example. This optical element is an example of an optical member for making the optical path length of the signal light coincide with the optical path length of the reference light.

  Some optical elements, such as prisms and lenses, disperse light. If the influence of the dispersion applied to the signal light is different from the influence of the dispersion applied to the reference light, the interference position of the signal light and the reference light is different for each wavelength component, and there is a possibility that suitable interference light cannot be obtained. . In order to avoid such a situation, it is possible to provide an optical member for making the influence of the dispersion applied to the signal light coincide with the influence of the dispersion applied to the reference light. As this optical member, for example, a prism member such as a pair prism, a liquid cell in which a liquid such as water is sealed, a glass block, or the like can be used.

  An optical member for matching the effects of the optical path length and dispersion is arranged on the optical path of the reference light alone, for example, between the beam splitter 7 and the reference mirror 9 in order to maintain the information included in the signal light. It is desirable that

  The optical system employed in the optical image measurement device 1 is merely an example of an optical system of a full-field optical image measurement device. For example, an arbitrary interferometer such as a Michelson type or a Mach-Cender type can be adopted.

  Here, an optical image measuring apparatus employing a Michelson interferometer will be described. The optical image measurement device 50 shown in FIG. 4 is an example of such an optical image measurement device.

  The optical image measuring device 50 includes a halogen lamp 51 as a light source. The halogen lamp 51 outputs, for example, non-polarized broadband light M. Although not shown, the halogen lamp 51 includes, together with a normal halogen lamp, an optical fiber bundle that guides the output light, a Kohler illumination optical system for uniformly illuminating the irradiation field of the output light, and the like. Can be configured. The non-polarized broadband light M output from the halogen lamp 51 has a predetermined beam diameter.

  The light source is not limited to the halogen lamp 51, and may be any light source that outputs non-polarized broadband light. For example, an arbitrary heat source such as a xenon lamp can be applied. The light source may be a laser light source that outputs broadband light with random polarization. Hereinafter, the case of non-polarized light will be described in detail.

  Now, the broadband light M output from the halogen lamp 51 includes light of various bands. The filter 52 is a filter that transmits only a predetermined band of the non-polarized broadband light M. The predetermined band to be transmitted is determined by the resolution, the measurement depth, and the like, and is set to a band having a center wavelength of about 760 nm and a wavelength width of about 100 nm, for example. The light transmitted through the filter 52 is also referred to as broadband light M.

  The non-polarized broadband light M transmitted through the filter 52 is divided into two by a beam splitter 53 such as a half mirror. That is, the reflected light from the beam splitter 53 forms the signal light S, and the light transmitted through the beam splitter 53 forms the reference light R.

  The non-polarized reference light R generated by the beam splitter 53 passes through the wave plate (λ / 4 plate) 54 and the polarizing plate 55 and is reflected by the reflection mirror 56. Further, the reference light R passes through the glass plate 57 and is focused on the reflection surface of the reference mirror 59 by the objective lens 58. The reference light R reflected by the reference mirror 59 returns to the beam splitter 53 via the same optical path in the reverse direction.

  At this time, the reference light R that was initially unpolarized is converted into circularly polarized light by passing through the wave plate 54 and the polarizing plate 55 twice. The glass plate 57 is an optical member for making the influences of dispersion generated in the optical paths (both arms of the interferometer) of the signal light S and the reference light R coincide.

  The reference mirror 59 can be moved by the reference mirror moving mechanism 60 in the traveling direction of the reference light R, that is, in the direction orthogonal to the reflecting surface of the reference mirror 59 (in the direction of the double-headed arrow in FIG. 4). The reference mirror moving mechanism 60 is configured to include driving means such as a piezo element.

  By moving the reference mirror 59 in this way, the optical path length difference between the signal light S and the reference light R is changed. Here, the optical path length of the signal light S is a reciprocating distance between the beam splitter 53 and the depth position of the object to be measured 5000 to be observed. The optical path length of the reference light R is a reciprocating distance between the beam splitter 53 and the reflecting surface of the reference mirror 59. By changing the difference between the optical path lengths of the signal light S and the reference light R, it is possible to selectively acquire images at various depth positions of the measured object 5000.

  In this embodiment, the optical path length difference is changed by changing the optical path length of the reference light R. However, the optical path length difference is changed by changing the optical path length of the signal light S. It is also possible to do. In that case, a configuration is provided in which the distance between the apparatus optical system and the eye to be examined is changed. Specifically, for example, a stage that moves the apparatus optical system in the z direction, a stage that moves the measured object 5000 in the z direction, and the like can be applied.

  The signal light S enters the optical fiber bundle 61 while maintaining a non-polarized state. When the beam diameter of the signal light S is larger than the diameter of the optical fiber bundle, an optical element such as a condenser lens for reducing the beam diameter of the signal light S is used as the beam splitter 53 and the optical fiber bundle 61. You may arrange | position between.

  The optical fiber bundle 61 has the same configuration as the optical fiber bundle 5 of the above embodiment. In addition, the optical fiber bundle 61 of this modification is not provided with a reflection means and a division means like the reflection part 6 of the said embodiment. Microlenses are respectively provided at the distal end portions (end portions on the measured object 5000 side) of the respective optical fibers forming the optical fiber bundle 61 (refer to FIG. 2). The signal light S guided to each optical fiber is focused at the depth position of the observation target of the measured object 5000 by the microlens.

  The signal light S irradiated on the object to be measured 5000 is reflected and scattered on the surface and inside of the object to be measured 5000 and enters the optical fiber bundle 61 from the tip. Further, the signal light S is guided by the optical fiber bundle 61, exits from the base end portion (the end portion on the opposite side of the tip end portion), and returns to the beam splitter 3.

  The signal light S that has passed through the measured object 5000 and the reference light R that has passed through the reference mirror 59 are superimposed by the beam splitter 53 to generate interference light L. The interference light L includes an S-polarized component and a P-polarized component. An interferometer including the halogen lamp 51, the beam splitter 53, and the reference mirror 59 is an example of the “interference light generating means” of the present invention.

  The interference light L generated by the beam splitter 53 passes through the aperture stop 62 and becomes focused light by the imaging lens (group) 63. The S-polarized component L 1 of the interference light L that has become the focused light is reflected by the polarization beam splitter 64 and detected by a CCD (image sensor) 66. On the other hand, the P-polarized component L2 of the interference light L passes through the polarization beam splitter 64, is reflected by the reflection mirror 65, and is detected by a CCD (image sensor) 67.

  Each of the CCDs 66 and 67 has a two-dimensional light receiving surface. The S-polarized component L1 and the P-polarized component L2 are irradiated on the light receiving surfaces of the CCDs 66 and 67 with a predetermined beam diameter, respectively.

  The CCDs 66 and 67 that have detected the S-polarized component L1 and the P-polarized component L2 respectively send detection signals to the computer 68. The CCDs 66 and 67 are examples of the “detecting means” of the present invention. A two-dimensional photosensor array other than a CCD may be used as the detection means.

Since the reference light R that is the source of the interference light L is circularly polarized and the signal light S is non-polarized, the S-polarized component L1 and the P-polarized component L2 have a phase difference of 90 degrees (π / 2). . Therefore, a detection signal _{D A} outputted from the CCD 66, the detection signal _{D B} outputted from the CCD67 has a phase difference of 90 degrees. Therefore, these detection signals can be expressed as the above-described equations (1) and (2).

Similarly to the above embodiment, the computer 68 controls the reference mirror moving mechanism 60 to switch the optical path length of the reference light R, and causes a new measurement to be executed in that state. Accordingly, the CCDs 66 and 67 output new detection signals D _A ′ and D _B ′.

Here, the optical path length of the reference light R in the optical path length and the next measurement of the reference light R in the first measurement has a detection signal D _A detection signal D _{A 'is} a phase difference 180 degrees ([pi), In addition, the detection signal D _B and the detection signal D _B ′ are set in advance so as to have a distance interval having a phase difference of 180 degrees (π). Since the detection signals D _A and D _B have a phase difference of 90 degrees, four detection signals D _A , D _B , D _A ′, and D _B ′ for each phase difference of 90 degrees are obtained.

The computer 68 adds the detection signals D _A and D _A ′ (phase difference 180 degrees) and divides the sum by 2 to obtain the background light component I _s (x, y) + I _r (x, y). Calculate. This calculation process detection signal _{D B,} may be carried out using _D B '(phase difference of 180 degrees).

Further, the computer 68 divides the obtained background light component I _s (x, y) + I _r (x, y) from the respective detection signals D _A and D _B to obtain an interference component (cos component, sin component). Then, the computer 68 calculates a sum of squares of the interference components of the detection signals D _A and D _B to form a tomographic image having a cross section in the direction (xy direction, horizontal direction) orthogonal to the z direction.

  The computer 68 displays the formed tomographic image. The computer 68 has the same configuration as the computer 16 of the above embodiment (see FIG. 3).

  According to the optical image measurement device 50 to which such a Michelson interferometer is applied, the tip portion thereof is arranged near the deep tissue of the object 5000 to be measured, for example, the optical fiber bundle 61 is inserted into the subject. Can be measured.

  Furthermore, according to the optical image measurement device 50, it is possible to form an image having a resolution of μm level of the deep tissue by using the OCT technique.

  Thus, according to the optical image measurement device 50, it is possible to image the fine structure of the deep tissue of the object to be measured.

  Moreover, what has flexibility as the optical fiber bundle 61 can be used. Thereby, for example, the optical fiber bundle 61 can be suitably inserted into the subject. In particular, when the path from the opening on the surface of the subject to the deep tissue is bent, the optical fiber bundle 61 can be suitably guided to the vicinity of the deep tissue.

<Second Embodiment>
Application examples of the present invention to Fourier domain type and swept source type optical image measurement devices will be described.

[Device configuration]
An optical image measurement apparatus 80 shown in FIG. 5 is an apparatus that can perform tomographic imaging of a measurement object 5000 using the OCT technique and imaging of the surface of the measurement object 5000. The optical image measurement device 80 is a device for taking an image of a deep tissue in a subject such as a fundus or a viscera. In this embodiment, a case where the object to be measured 5000 is the fundus will be described.

  As shown in FIG. 5, the optical image measurement device 80 includes an optical system unit 80 </ b> A, an OCT unit 150, and a computer 200. The optical system unit 80A has an optical system for taking a two-dimensional image of the surface of the measured object 5000. Here, since the object 5000 to be measured is the fundus, the optical system unit 80A is configured in substantially the same manner as a conventional fundus camera. The OCT unit 150 stores an optical system for taking an image using the OCT technique. The computer 200 includes a computer that executes various arithmetic processes and control processes.

  One end of a connection line 152 is attached to the OCT unit 150. A connector portion 151 for connecting the connection line 152 to the optical system unit 80A is attached to the other end of the connection line 152. An optical fiber is conducted through the connection line 152. As described above, the OCT unit 150 and the optical system unit 80 </ b> A are optically connected via the connection line 152.

[Configuration of optical system unit]
The optical system unit 80A is used to form a two-dimensional image of the surface of the measured object 5000 based on optically acquired data (data detected by the imaging devices 145 and 146).

  Here, the two-dimensional image of the surface of the measured object 5000 represents a color image, a monochrome image, or the like obtained by photographing the surface of the measured object 5000. Furthermore, a fluorescence image (fluorescein fluorescence image, indocyanine green fluorescence image, etc.) of the fundus as the measurement object 5000 is also included in the two-dimensional image. Similarly to the conventional fundus camera, the optical system unit 80A includes an illumination optical system 100 that illuminates the object to be measured 5000, and a photographing optical system 120 that guides the fundus reflection light of the illumination light to the imaging devices 145 and 146. Yes.

  The imaging device 145 detects illumination light having a wavelength in the near infrared region. Further, the imaging device 146 detects illumination light having a wavelength in the visible region. Further, the imaging optical system 120 operates to guide the signal light from the OCT unit 150 to the object to be measured 5000 and to guide the signal light passing through the object to be measured 5000 to the OCT unit 150.

  The illumination optical system 100 includes an observation light source 101, a condenser lens 102, a photographing light source 103, a condenser lens 104, exciter filters 105 and 106, a ring translucent plate 107, a mirror 108, an LCD (Liquid Crystal Display) 109, an illumination diaphragm 110, a relay. A lens 111, a perforated mirror 112, and an optical fiber bundle 113 are included.

  The observation light source 101 outputs illumination light having a wavelength in the visible region included in a range of about 400 nm to 700 nm, for example. Moreover, the imaging light source 103 outputs illumination light having a wavelength in the near-infrared region included in a range of about 700 nm to 800 nm, for example. Near-infrared light output from the imaging light source 103 is set to be shorter than the wavelength of light used in the OCT unit 150.

  The optical fiber bundle 113 has the same configuration as the optical fiber bundle 5 of the first embodiment described above (see FIG. 2). That is, the optical fiber bundle 113 is configured by bundling a plurality of optical fibers, and a microlens is provided at the tip of each optical fiber (the end on the measured object 5000 side). The optical fiber bundle 113 is not provided with a dividing unit or a reflecting unit like the reflecting unit 6 of FIG.

  The photographing optical system 120 includes an optical fiber bundle 113, a perforated mirror 112 (hole 112a), a photographing aperture 121, barrier filters 122 and 123, a variable power lens 124, a relay lens 125, a photographing lens 126, a dichroic mirror 134, a field. A lens 128, a half mirror 135, a relay lens 131, a dichroic mirror 136, a photographing lens 133, an imaging device 145 (imaging device 145a), a reflection mirror 137, a photographing lens 138, an imaging device 146 (imaging device 146a), a lens 139, and an LCD 140. Consists of including.

  Further, the photographing optical system 120 is provided with a dichroic mirror 134, a half mirror 135, a dichroic mirror 136, a reflection mirror 137, a photographing lens 138, a lens 139, and an LCD 140.

  The dichroic mirror 134 reflects the fundus reflection light (having a wavelength included in the range of about 400 nm to 800 nm) of the illumination light from the illumination optical system 100 and the signal light LS (for example, about 800 nm to 900 nm) from the OCT unit 150. Having a wavelength included in the range (described later).

  Further, the dichroic mirror 136 transmits illumination light having a wavelength in the visible region from the illumination optical system 100 (visible light having a wavelength of about 400 nm to 700 nm output from the observation light source 101) and changes the wavelength in the near infrared region. It is configured to reflect the illumination light it has (near infrared light with a wavelength of about 700 nm to 800 nm output from the imaging light source 103).

  The LCD 140 displays a fixation target (internal fixation target) for fixing the eye to be examined. The light from the LCD 140 is collected by the lens 139, reflected by the half mirror 135, and then reflected by the dichroic mirror 136 via the field lens 128. Further, this light is incident on the eye to be examined through the photographing lens 126, the relay lens 125, the variable power lens 124, the aperture mirror 112 (the aperture 112a thereof), the optical fiber bundle 113, and the like. As a result, the internal fixation target is projected onto the object 5000 to be measured.

  The image sensor 145a is an image sensor such as a CCD or CMOS built in the image pickup device 145 such as a TV camera, and particularly detects light having a wavelength in the near infrared region. That is, the imaging device 145 is an infrared television camera that detects near infrared light. The imaging device 145 outputs a video signal as a result of detecting near infrared light.

  The touch panel monitor 147 displays a two-dimensional image (fundus image) of the surface of the measured object 5000 based on this video signal. The video signal is sent to the computer 200, and a fundus image is displayed on the display.

  Note that illumination light having a wavelength in the near-infrared region output from the photographing light source 103 is used at the time of photographing by the imaging device 145, for example.

  On the other hand, the image pickup device 146a is an image pickup device such as a CCD or a CMOS built in the image pickup device 146 such as a television camera, and particularly detects light having a wavelength in the visible region. That is, the imaging device 146 is a television camera that detects visible light. The imaging device 146 outputs a video signal as a result of detecting visible light.

  The touch panel monitor 147 displays a two-dimensional image (fundus image) of the surface of the measured object 5000 based on this video signal. The video signal is sent to the computer 200, and a fundus image is displayed on the display.

  Note that illumination light having a wavelength in the visible region output from the observation light source 101 of the illumination optical system 100 is used at the time of photographing by the imaging device 146, for example.

  The optical system unit 80A is provided with a scanning unit 141 and a lens 142. The scanning unit 141 has a configuration for scanning the irradiation position of the light to be measured 5000 (signal light LS; described later) output from the OCT unit 150.

  As described in the first embodiment (see FIG. 2), the optical fiber bundle 113 is provided with a plurality of optical fibers. The scanning unit 141 scans the irradiation position of the signal light LS on the measured object 5000 by sequentially causing the signal light LS to enter the plurality of optical fibers.

  The lens 142 makes the signal light LS guided from the OCT unit 150 through the connection line 152 enter the scanning unit 141 as a parallel light beam. The lens 142 focuses the fundus reflection light of the signal light LS that has passed through the scanning unit 141.

  FIG. 6 shows an example of the configuration of the scanning unit 141. The scanning unit 141 includes galvanometer mirrors 141A and 141B and reflection mirrors 141C and 141D.

  Galvano mirrors 141A and 141B are reflection mirrors arranged so as to be rotatable about rotation shafts 141a and 141b, respectively. The galvanometer mirrors 141A and 141B are rotated around the rotation shafts 141a and 141b by a driving mechanism (not shown). Thereby, the direction of the reflection surface (surface that reflects the signal light LS) of each galvanometer mirror 141A, 141B is changed.

  The rotating shafts 141a and 141b are disposed orthogonal to each other. In FIG. 6, the rotation shaft 141a of the galvano mirror 141A is arranged in a direction parallel to the paper surface. Further, the rotation shaft 141b of the galvanometer mirror 141B is disposed in a direction orthogonal to the paper surface.

  That is, the galvano mirror 141B is configured to be rotatable in a direction indicated by a double-sided arrow in FIG. 6, and the galvano mirror 141A is configured to be rotatable in a direction orthogonal to the double-sided arrow. Accordingly, the galvanometer mirrors 141A and 141B act so as to change the reflection direction of the signal light LS to directions orthogonal to each other. 5 and 6, when the galvano mirror 141A is rotated, the signal light LS is scanned in the x direction, and when the galvano mirror 141B is rotated, the signal light LS is scanned in the y direction.

  The signal light LS reflected by the galvanometer mirrors 141A and 141B is reflected by the reflection mirrors 141C and 141D and travels in the same direction as when incident on the galvanometer mirror 141A.

  Note that the end surface 152 b of the optical fiber 152 a inside the connection line 152 is disposed to face the lens 142. The signal light LS emitted from the end face 152b travels toward the lens 142 while expanding the beam diameter, and is converted into a parallel light flux by the lens 142. Conversely, the signal light LS that has passed through the measured object 5000 is converged toward the end face 152b by the lens 142 and enters the optical fiber 152a.

[Configuration of OCT unit]
Next, the configuration of the OCT unit 150 will be described with reference to FIG. The OCT unit 150 is a device for forming a tomographic image of the measured object 5000 based on optically acquired data (data detected by the CCD 184; described later). This tomographic image is a tomographic image in a cross section including the z direction.

  The OCT unit 150 includes an optical system that is almost the same as a conventional Fourier domain type optical image measurement apparatus. That is, the OCT unit 150 divides low-coherence light into reference light and signal light, and superimposes the signal light passing through the object to be measured and the reference light passing through the reference object to generate interference light and detect it. To do. This detection result (detection signal) is input to the computer 200. The computer 200 analyzes this detection signal and forms a tomographic image of the measured object.

  The low coherence light source 160 is configured by a broadband light source such as a super luminescent diode (SLD) or a light emitting diode (LED) that outputs low coherence light L0. As the low coherence light L0, for example, light including light having a wavelength in the near infrared region and having a temporal coherence length of about several tens of micrometers is used.

  The low coherence light L0 has a longer wavelength than the illumination light (wavelength of about 400 nm to 800 nm) of the optical system unit 80A, for example, a wavelength included in a range of about 800 nm to 900 nm.

  The low coherence light L0 output from the low coherence light source 160 is guided to the optical coupler 162 through the optical fiber 161. The optical fiber 161 is constituted by, for example, a single mode fiber or a PM fiber (Polarization maintaining fiber). The optical coupler 162 splits the low coherence light L0 into the reference light LR and the signal light LS.

  The optical coupler 162 functions as both a means for splitting light (splitter) and a means for superposing light (coupler). Here, it is conventionally referred to as an “optical coupler”. I will call it.

  The reference light LR generated by the optical coupler 162 is guided by an optical fiber 163 made of a single mode fiber or the like and emitted from the end face of the fiber. Further, the reference light LR is collimated by the collimator lens 171 and then reflected by the reference mirror 174 via the optical fiber (bundle) and the density filter 173. The reference mirror 174 is an example of the “reference object” in the present invention.

  The reference light LR reflected by the reference mirror 174 passes through the density filter 173 and the optical fiber 172 again, is condensed on the fiber end face of the optical fiber 163 by the collimator lens 171, and is guided to the optical coupler 162 through the optical fiber 163.

  Here, the optical fiber 172 and the density filter 173 are used as optical members for matching the optical path lengths (optical distances) of the reference light LR and the signal light LS, and the dispersion of the light applied to the reference light LR and the signal light LS, respectively. Acts as an optical member for matching the influences.

  Further, the density filter 173 also functions as a neutral density filter that reduces the amount of reference light, and is constituted by, for example, a rotating ND (Neutral Density) filter. The density filter 173 is rotationally driven by a drive mechanism (not shown) including a drive device such as a motor, thereby changing the amount of decrease in the light amount of the reference light LR. Thereby, the light quantity of the reference light LR that contributes to the generation of the interference light LC can be changed.

  Further, the reference mirror 174 is moved in the traveling direction of the reference light LR (the direction of the double-sided arrow shown in FIG. 7). Thereby, the optical path length of the reference light LR according to the axial length of the eye to be examined can be secured. Further, by moving the reference mirror 174, it is possible to acquire an image at an arbitrary depth position of the measured object 5000. The reference mirror 174 is moved by a drive mechanism (not shown) configured to include a drive device such as a motor.

  On the other hand, the signal light LS generated by the optical coupler 162 is guided to the end of the connection line 152 by an optical fiber 164 made of a single mode fiber or the like. An optical fiber 152 a is conducted inside the connection line 152. In addition, the optical fiber 164 and the optical fiber 152a may be formed from a single optical fiber, or may be formed integrally by joining the respective end faces. In any case, it is sufficient that the optical fibers 164 and 152a are configured to transmit the signal light LS between the optical system unit 80A and the OCT unit 150.

  The signal light LS is guided through the connection line 152 and guided to the optical system unit 80A. Further, the signal light LS passes through the lens 142, the scanning unit 141, the dichroic mirror 134, the photographing lens 126, the relay lens 125, the zoom lens 124, the photographing aperture 121, and the hole 112 a of the aperture mirror 112, and the optical fiber. The light enters the bundle 113. At this time, the signal light LS is scanned by the scanning unit 141 so as to enter a certain optical fiber (one or more optical fibers) of the optical fiber bundle 113. Then, the signal light LS is guided by the optical fiber, emitted from the distal end portion thereof, and applied to the object 5000 to be measured. When irradiating the measurement object 5000 (fundus) with the signal light LS, the barrier filters 122 and 123 are each retracted from the optical path in advance.

  The signal light LS incident on the measured object 5000 is imaged and reflected at the depth position of the observation target of the measured object 5000. At this time, the signal light LS is reflected and scattered on the surface of the measured object 5000 and the refractive index boundary of the deep region. Therefore, the signal light LS that has passed through the measured object 5000 includes information that reflects the backscattering state at the refractive index boundary around the depth position of the observation target. This light may be simply referred to as “fundus reflected light of the signal light LS”.

  The fundus reflected light of the signal light LS travels in the reverse direction in the optical system unit 80A, is condensed on the end surface 152b of the optical fiber 152a, enters the OCT unit 150 through the optical fiber 152, and passes through the optical fiber 164. Return to the optical coupler 162.

  The optical coupler 162 generates the interference light LC by superimposing the signal light LS that has passed through the measured object 5000 and the reference light LR that has passed through the reference mirror 174. The generated interference light LC is guided to the spectrometer 180 through an optical fiber 165 made of a single mode fiber or the like.

  In this embodiment, a Michelson interferometer is used. However, for example, any type of interferometer such as a Mach-Zehnder type can be appropriately used.

  The “interference light generating means” of the present invention includes, for example, an optical coupler 162 and an optical member on the optical path of the signal light LS (that is, an optical member disposed between the optical coupler 162 and the measured object 5000). And an optical member (that is, an optical member disposed between the optical coupler 162 and the reference mirror 174) on the optical path of the reference light LR. In particular, the interference light generation unit includes an optical coupler 162, optical fibers 163 and 164, a reference mirror 174, and an optical fiber bundle 113.

  The spectrometer (spectrometer) 180 includes a collimator lens 181, a diffraction grating 182, an imaging lens 183, and a CCD 184. The diffraction grating 182 may be a transmission type diffraction grating that transmits light, or may be a reflection type diffraction grating that reflects light. Further, instead of the CCD 184, other light detection elements such as CMOS can be used.

  The interference light LC incident on the spectrometer 180 is converted into a parallel light beam by the collimator lens 181, and is split (spectral decomposition) by the diffraction grating 182. The split interference light LC is imaged on the imaging surface of the CCD 184 by the imaging lens 183. The CCD 184 detects each spectrum of the separated interference light LC and converts it into an electrical signal, and outputs this detection signal to the computer 200. The CCD 184 is an example of the “detecting means” in the present invention.

[Computer configuration]
Next, the configuration of the computer 200 will be described. The computer 200 analyzes the detection signal input from the CCD 184 of the OCT unit 150 and forms a tomographic image of the object 5000 to be measured. The analysis method at this time is the same as the conventional Fourier domain OCT method.

  In addition, the computer 200 forms a two-dimensional image showing the surface form of the object to be measured 5000 based on video signals output from the imaging devices 145 and 146 of the optical system unit 80A. This two-dimensional image may be a still image or a moving image. The computer 200 controls the light sources 101 and 103 and the imaging devices 145 and 12 for acquiring these images.

  The computer 200 controls each part of the optical system unit 80A and the OCT unit 150.

  As control of the optical system unit 80A, the computer 200 controls the output of illumination light by the observation light source 101 and the imaging light source 103, controls the insertion / retraction operation of the exciter filters 105 and 106 and the barrier filters 122 and 123 on the optical path, and the LCD 140. Control of the display device such as the above, movement control of the illumination aperture 110 (control of the aperture value), control of the aperture value of the photographing aperture 121, movement control of the variable magnification lens 124 (control of magnification), and the like are performed. Furthermore, the computer 200 controls the operation of the galvanometer mirrors 141A and 141B.

  As control of the OCT unit 150, the computer 200 controls the output of the low-coherence light L0 by the low-coherence light source 160, the movement control of the reference mirror 174, and the rotation operation of the density filter 173 (change in the amount of decrease in the light amount of the reference light LR). Operation), control of the accumulation time of the CCD 184, and the like.

  The computer 200 includes a microprocessor, a RAM, a ROM, a hard disk drive, a keyboard, a mouse, a display, a communication interface (I / F), and the like, similar to a conventional computer. Further, the computer 200 is provided with an image forming board for forming a tomographic image of the measured object 5000.

[Mode of operation]
An example of the operation mode of the optical image measurement device 80 according to this embodiment will be described.

  A two-dimensional image (fundus image) of the surface of the measurement object 5000 is taken in the same manner as a conventional fundus camera. The optical image measurement device 80 is different from the conventional fundus camera in that the illumination light for photographing the fundus image is illuminated on the fundus via the optical fiber bundle 113, but the rest is the same. When photographing a fundus image, it is possible to retract the optical fiber bundle 113 from the optical path and place the objective lens on the optical path instead. In this case, it is possible to take a fundus image as in a conventional fundus camera.

  Hereinafter, image measurement to which the OCT technique is applied will be described. Here, the number of optical fibers included in the optical fiber bundle 113 is M.

  First, the computer 200 controls the scanning unit 141 so that the signal light LS is incident on the first optical fiber of the optical fiber bundle 113, and turns on the low-coherence light source 160. Accordingly, the first interference light LC based on the signal light LS and the reference light LR that has passed through the position (first position) of the measured object 5000 corresponding to the first optical fiber is detected.

  The computer 200 forms an image in the depth direction (z direction) at the first position based on the first interference light LC.

  Since the position of each optical fiber is constant, the positions of the galvanometer mirrors 141A and 141B for allowing the signal light LS to enter the first optical fiber can be determined in advance. The computer 200 stores the positions of the galvanometer mirrors 141A and 141B in advance (the same applies hereinafter).

  Next, the computer 200 controls the scanning unit 141 so that the signal light LS enters the second optical fiber, and turns on the low-coherence light source 160. Thereby, the second interference light LC based on the signal light LS passing through the position (second position) of the measured object 5000 corresponding to the second optical fiber and the reference light LR is detected.

  The computer 200 forms an image in the depth direction at the second position based on the second interference light LC.

  As described above, the optical image measurement device 80 performs measurement by sequentially causing the signal light LS to enter the M optical fibers, and sequentially forms images in the depth direction at the first to Mth positions. . The computer 200 forms a tomographic image of the object to be measured 5000 based on these M images in the depth direction. At this time, the computer 200 forms a tomographic image by arranging the images in the depth direction based on the arrangement information (stored in advance) of the M optical fibers.

[Action / Effect]
The operation and effect of the optical image measurement device 80 will be described.

  The optical image measurement device 80 divides the low-coherence light into signal light and reference light, and generates interference light by superimposing the signal light passing through the object to be measured and the reference light passing through the reference object. Means, a CCD 184 for detecting the interference light, and a computer 200 for forming an image of the object to be measured based on the detection result of the interference light.

  The optical fiber bundle 113 is an example of the “light guide” in the present invention. In other words, the optical fiber bundle 113 acts to emit the signal light divided from the low-coherence light from the tip and guide the signal light incident from the tip via the object to be measured. Then, the interference light generation means acts to generate the interference light by superimposing the signal light guided by the optical fiber bundle 113 with the reference light.

  According to such an optical image measuring device 80, for example, the optical fiber bundle 113 can be inserted into the subject, and the tip can be placed near the deep tissue of the object 5000 to be measured.

  Furthermore, according to the optical image measurement device 80, it is possible to form an image having a resolution of μm level of deep tissue by using the OCT technique.

  Thus, according to the optical image measurement device 80, it is possible to image the fine structure of the deep tissue of the object to be measured.

  Further, by using a flexible one as the optical fiber bundle 113, for example, the optical fiber bundle 113 can be suitably inserted into the subject.

[Modification]
A modification of the optical image measurement device according to this embodiment will be described.

  In the second embodiment, the optical image measurement device 80 used to acquire the fundus image has been described in detail. However, the optical image measurement device according to this embodiment is not limited to this.

  An example of an optical image measurement device according to this embodiment is shown in FIG. The optical image measurement device 300 includes an optical system unit 301 and a computer 312. The computer 312 controls the optical system unit 301.

  The low coherence light output from the low coherence light source 302 is guided to the optical coupler 304 through the optical fiber 303. The optical coupler 304 splits the low coherence light into signal light and reference light.

  The reference light is guided to the reference mirror 306 by the optical fiber 305 and reflected. This reflected light is guided to the optical coupler 304 by the optical fiber 305.

  The signal light is guided to the scanning unit 308 by the optical fiber 307. Similar to the first embodiment, the optical fiber bundle 309 is configured by bundling a plurality of optical fibers (see FIG. 2). The scanning unit 308 causes the signal light to be incident on one (or two or more) proximal ends (ends on the scanning unit 308 side) of the plurality of optical fibers.

  The scanning unit 308 may have a configuration including a galvano mirror or the like like the scanning unit 141 of the above embodiment, or may have a configuration other than that. That is, the configuration of the scanning unit 308 is arbitrary as long as it operates to sequentially guide the signal light to the plurality of fibers included in the optical fiber bundle 309.

  The signal light guided by a certain optical fiber of the optical fiber bundle 309 is focused by the microlens at the tip of the optical fiber, and is reflected and scattered around the depth position of the object to be measured 5000 to be observed. The The reflected light or scattered light enters the tip of the optical fiber, is guided by the optical fiber, and returns to the optical coupler 304 via the scanning unit 308 and the optical fiber 307.

  The optical coupler 304 generates interference light by superimposing the reference light and the signal light on each other. This interference light is guided to the spectrometer 311 by the optical fiber 310. The spectrometer 311 detects the spectral component of the interference light and outputs a detection signal to the computer 312.

  Based on this detection signal, the computer 312 forms a one-dimensional image in the depth direction at a site where the signal light is reflected and scattered.

  The optical image measurement device 300 repeats measurement by causing the scanning unit 308 to sequentially make signal light incident on each of the plurality of optical fibers included in the optical fiber bundle 309. The spectrometer 311 sequentially detects spectral components of interference light corresponding to the plurality of optical fibers. The computer 312 sequentially forms one-dimensional images in the depth direction at different positions of the measured object 5000 based on the detection signals sequentially output from the spectrometer 311. Further, the computer 312 forms a tomographic image of the measured object 5000 based on these one-dimensional images.

  According to such an optical image measurement device 300, as in the optical image measurement device 80 according to the second embodiment, it is possible to image the fine structure of the deep tissue of the measurement object.

  An optical member for matching the optical path length of the signal light and the optical path length of the reference light can be provided on the optical path of the reference light, for example. Further, an optical member for making the influence of the dispersion imparted to the signal light coincide with the influence of the dispersion imparted to the reference light can be provided, for example, on the optical path of the reference light.

  Another example of the optical image measurement device according to this embodiment is shown in FIG. This modification relates to a configuration in which an optical fiber bundle includes a dividing unit.

  The low-coherence light output from the low-coherence light source 401 of the optical image measurement device 400 shown in FIG. 9 passes through the beam splitter 402 and enters the scanning unit 403.

  Similarly to the above-described embodiment, the scanning unit 403 scans the base end portion (end portion on the scanning unit 403 side) of the optical fiber bundle 404 with low coherence light. That is, the scanning unit 403 sequentially causes low coherence light to enter a plurality of optical fibers included in the optical fiber bundle 404.

  The optical fiber bundle 404 is provided with a reflecting portion 405. The reflection unit 405 reflects a part of the low-coherence light that travels in the optical fiber bundle 404 toward the tip. The low coherence light reflected by the reflection unit 405 is used as reference light. On the other hand, the low coherence light transmitted through the reflecting portion 405 is used as signal light. The reflector 405 is an example of the “dividing means” and “reflecting means” of the present invention.

  The reflection unit 405 can be provided at an arbitrary position of the optical fiber bundle 404 as in the first embodiment.

  The reference light composed of the low-coherence light reflected by the reflection unit 405 is emitted from the proximal end portion of the optical fiber bundle 404 and is reflected by the beam splitter 402 via the scanning unit 403. Further, the reference light is reflected by the beam splitter 406 and reaches the reference mirror 407.

  The reference light reflected by the reference mirror 407 passes through the beam splitter 406, is reflected by the reflection mirror 408, and reaches the beam splitter 410.

  The reference mirror 407 is movable in the direction of the double-sided arrow shown in FIG. Thereby, images of various depth positions of the measured object 5000 can be acquired.

  On the other hand, the signal light composed of low-coherence light that has passed through the reflecting portion 405 is emitted from the tip portion of the optical fiber bundle 404. A microlens is provided at the tip of each optical fiber included in the optical fiber bundle 404.

  The signal light applied to the measured object 5000 is reflected and scattered at various depth positions of the measured object 5000. The reflected or scattered light of the signal light enters the optical fiber via the microlens. Further, the signal light is guided by the optical fiber and emitted from the base end portion.

  The signal light emitted from the base end portion is reflected by the beam splitter 402 through the scanning unit 403, passes through the beam splitter 406, is reflected by the reflection mirror 409, and reaches the beam splitter 410.

  The reference light reflected by the beam splitter 410 and the signal light transmitted through the beam splitter 410 are superimposed on each other to generate interference light. This interference light is guided to a spectrometer 411, and its spectral component is detected.

  The spectrometer 411 sends the detection result (detection signal) of the spectral component of the interference light to the computer 412. The spectrometer 411 is an example of the “detecting means” in the present invention.

  Based on the detection signal from the spectrometer 411, the computer 412 forms a one-dimensional image in the depth direction at a site where the signal light is reflected and scattered.

  The optical image measurement apparatus 400 repeats measurement by causing the scanning unit 403 to sequentially make low coherence light incident on each of a plurality of optical fibers included in the optical fiber bundle 404. The spectrometer 411 sequentially detects the spectral components of the interference light corresponding to the plurality of optical fibers. The computer 412 sequentially forms one-dimensional images in the depth direction at different positions of the measured object 5000 based on detection signals sequentially output from the spectrometer 411. Further, the computer 412 forms a tomographic image of the measured object 5000 based on these one-dimensional images.

  According to such an optical image measurement device 400, as in the optical image measurement device 80 according to the second embodiment, it is possible to image the fine structure of the deep tissue of the object to be measured.

  An optical member for matching the optical path length of the signal light and the optical path length of the reference light can be provided on the optical path of the reference light, for example. Further, an optical member for making the influence of the dispersion imparted to the signal light coincide with the influence of the dispersion imparted to the reference light can be provided, for example, on the optical path of the reference light.

  The swept source optical image measurement device is configured in substantially the same manner as the Fourier domain optical image measurement device described above. That is, the swept source type optical image measurement device includes a light source (high-speed wavelength scanning laser) that switches and outputs light of various frequencies at high speed, and detects interference light based on the light of each frequency, and the detection result Is configured to form a tomographic image of the object to be measured.

  In the optical image measurement device according to this embodiment, it is desirable that signal light (or low coherence light) be accurately incident on each of a plurality of optical fibers included in the optical fiber bundle. is required. In particular, when the interval between adjacent optical fibers is small, it is necessary to perform extremely high-precision control. Accordingly, the signal light (or low-coherence light) is scanned with a predetermined accuracy on the end face of the base end part of the optical fiber bundle (the array surface of the base end parts of the plurality of optical fibers), and the preferable result obtained thereby. It is possible to configure to form an image based on only the interference light. In addition, suitable interference light means the interference light etc. which have the intensity | strength more than predetermined value, for example.

It is the schematic showing an example of the structure of 1st Embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of the structure of 1st Embodiment of the optical image measuring device which concerns on this invention. It is a schematic block diagram showing an example of composition of a 1st embodiment of an optical image measuring device concerning this invention. It is the schematic showing an example of a structure of the modification of 1st Embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of a structure of 2nd Embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of a structure of 2nd Embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of a structure of 2nd Embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of a structure of the modification of 2nd Embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of a structure of the modification of 2nd Embodiment of the optical image measuring device which concerns on this invention. It is the schematic showing an example of a structure of the conventional optical image measuring device. It is the schematic showing an example of a structure of the conventional optical image measuring device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical image measuring device 2 Light source 3, 7, 12 Beam splitter 4 Polarizing element 5 Optical fiber bundle 5a Base end part 5b End part 5 alpha Optical fiber 5 beta Micro lens 6 Reflecting part 8 Wavelength plate 9 Reference mirror 10, 11 Reflecting mirror 13 Polarization Beam splitters 14 and 15 Two-dimensional photosensor array 16 Computer 17 Control unit 18 Display unit 19 Operation unit 20 Signal processing unit

Claims (11)

An interference light generating unit that divides low-coherence light into signal light and reference light, and generates interference light by superimposing the signal light passing through the object to be measured and the reference light passing through the reference object;
Detecting means for detecting the interference light;
Image forming means for forming an image of the object to be measured based on the detection result of the interference light;
An optical image measuring device having
The interference light generating means includes a light guide means for emitting signal light divided from low-coherence light from one end and guiding the signal light incident on the one end via the measured object, Interference light is generated by superimposing the guided signal light with reference light;
An optical image measuring device characterized by that. The light guiding means is flexible;
The optical image measuring device according to claim 1. The light guiding unit includes a dividing unit that divides low-coherence light incident from the other end into signal light and reference light, emits the signal light from the one end, and passes through the object to be measured from the one end. The incident signal light is guided to the other end and emitted, and the reference light is emitted from the other end,
The interference light generating means generates the interference light by superimposing the signal light and the reference light respectively emitted from the other end;
The optical image measurement device according to claim 1 or claim 2, wherein The light guiding means includes an optical fiber bundle,
The optical image measurement device according to any one of claims 1 to 3, wherein The light guide means includes an optical fiber bundle having the one end and the other end as both ends,
The dividing means includes reflecting means for reflecting a part of the low coherence light guided toward the one end and dividing the low coherence light into signal light and reference light.
The optical image measuring device according to claim 3. A microlens is provided at the one end of each fiber of the optical fiber bundle,
The optical image measuring device according to claim 4, wherein the optical image measuring device is an optical image measuring device. The detection means includes a two-dimensional photosensor array that simultaneously detects a plurality of interference lights based on a plurality of signal lights guided by a plurality of fibers included in the optical fiber bundle,
The optical image measurement device according to any one of claims 4 to 6, wherein the optical image measurement device is an optical image measurement device. The interference light generation means sequentially guides signal light to a plurality of fibers included in the optical fiber bundle,
The detection means sequentially detects interference light based on the sequentially guided signal light,
The image forming means sequentially forms images of a plurality of different parts of the object to be measured based on the sequentially detected interference lights.
The optical image measurement device according to any one of claims 4 to 6, wherein the optical image measurement device is an optical image measurement device. The interference light generating means includes an optical member for making the optical path length of the signal light coincide with the optical path length of the reference light,
The optical image measuring device according to any one of claims 1 to 8, wherein The interference light generation means includes an optical member for making the influence of dispersion imparted to the signal light coincide with the influence of dispersion imparted to the reference light.
The optical image measuring device according to any one of claims 1 to 8, wherein The optical member is provided on the optical path of the reference light.
The optical image measurement device according to claim 9 or 10,

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